Living with diabetes blog

Diabetes: Balancing your insulin, medication and exercise

Controlling diabetes is a balancing act. You must carefully balance food, activity (exercise), and medications and insulin. All three are equally important to your health, and each can increase or decrease your blood glucose levels. Many of our readers ask if they need to adjust their insulin or medication before exercise.

Physical activity, or exercise, includes anything that gets you moving, such as walking, dancing or working in your garden. Staying active improves your overall health. Regular exercise helps you:

Better control glucose levels

Increase overall fitness

Feel more energetic

Improve flexibility

Improve blood pressure

Lower your risk of developing cardiovascular disease

Improve your appearance, weight and overall sense of well-being

Insulin and diabetes medications lower your blood glucose. The amount of medication you need is unique to you. The time of day you take your medication and how much you take are important factors in allowing your medication to work when your blood glucose rises.

As you make exercise a part of your life, your diabetes health care provider may change or adjust your medications based on the results recorded in your diabetes record book. It's a balancing act — if you eat more than your meal plan allows, your blood glucose level may rise, or, if you exercise less than usual, your blood glucose level may rise.

Several factors affect your blood glucose during activity or exercise:

Your physical condition

Length of activity or exercise

Type of activity or exercise

Blood glucose level prior to exercising

When you're more active than usual, your blood glucose may drop too low, causing low blood glucose (hypoglycemia). It's important that you prepare ahead of time. If you're taking insulin and you know ahead of time when you will exercise, decrease your rapid or short insulin meal dose before the activity instead of taking extra food during the activity. Talk with your diabetes health care team for help making the decision about how much to decrease your insulin dose.

Also, avoid injecting insulin into your arms and legs that you will use during your activity or exercise. An abdominal injection site may help lower the risk for hypoglycemia associated with exercise.

Some additional tips:

Test your blood glucose before, during and after the activity to monitor how it affects your blood glucose level. This is important when beginning or changing your exercise program.

When your insulin is peaking, exercise isn't recommended, as it may lead to low blood glucose. Before you exercise, take less insulin or eat more food at mealtime or as a snack.

If your blood glucose is less than 70 mg/dL (3.8 mmol/L), take 1 to 2 carbohydrate choices and make sure your blood glucose is in goal range before you begin the activity or exercise.

If you were in goal range before the activity and the activity drops your blood glucose more than 30 to 50 mg/dL (1.6 to 2.7 mmol/L) or hypoglycemia occurs — blood glucose less than 70 mg/dL (3.8 mmol/L) — stop exercising and take 1 carbohydrate choice. Recheck your blood glucose after 15 minutes and repeat until your blood sugar returns to a safe range. Then, return to your exercise and take 1 carbohydrate every 30 to 60 minutes while you're active.

Don't exercise if your blood glucose is greater than 300 mg/dL (16 mmol/L). Exercising with blood glucoses over 300 mg/dL (16 mmol/L) can raise your blood glucose even more, because exercise causes the body to release or produce extra glucose and there won't be enough insulin available to use it.

With harder or more strenuous activity, even if you're within goal range or above goal, 2 carbohydrate choices may be necessary to prevent low blood glucose. Ask your health care provider if you have questions about this.

For longer duration or very strenuous activities, such as downhill/cross country skiing or long bike rides, take 1 carbohydrate choice every 30 to 60 minutes during the activity. Check your blood glucose every 1 to 2 hours during the activity.

It isn't recommended that you be active or exercise when you're sick.

We generally don't recommend exercising before bed due to the risk of delayed post-exercise hypoglycemia. If evening exercise is necessary, consider eating an extra carbohydrate after exercise to reduce the risk of hypoglycemia while sleeping.

Remember, it's essential to check with your health care provider if you've been sedentary and want to begin an exercise routine.

Didn't answer my question.
I am a thin individual with type 2 diabetes, caused by a whipple surgery. If my blood sugar is 94 before breakfast and I take the prescribed amount of insulin (4 units) and then exercise within I/2 hour after breakfast, my blood levels will drop drastically after the exercise. Should I eat more carbs and take less insulin, wait about an hour and then exercise?

Mark Swartz

November 9, 2016 1:42 p.m.

This information was so helpful thank

Esther

November 8, 2016 5:27 p.m.

Please talk about high blood sugars. I struggle with them daily even with an insulin pump.

Victoria

November 8, 2016 11:34 a.m.

Great info.

Stavros

September 9, 2016 11:37 p.m.

Thanks for the great content. you have helped me fill knowledge gaps. Thanks

Melissa Tower

March 11, 2016 12:51 p.m.

Very helpful. I'm 69 years old and a type1 diabetic since age 19. We bike, kayak and/or walk everyday. What make it difficult to maintain proper levels, is not the activity, but what that activity may entail. For example, we went kayaking and needed to carry two kayaks 100 yards to reach the water and then back to the car after 2 hours in the water. That was too much and blood sugar level dropped dangerously low. Yes I had my moniter and plenty of snacks but not for that activity. Energy conservation is also very important. Get the details about any activity and skip those that may zap you before you begin. Conserve energy and use it to have fun!!

Frank M

March 18, 2015 5:03 a.m.

good article. useful

joseph kirema

March 17, 2015 4:00 p.m.

Thank you Peggy,
I have been type 1 diabetic for47 years. I agree with what you have said. And you said it very well. I am passing this onto my husband to read, so he better understands.
Ann

Ann Pownall

March 17, 2015 1:53 p.m.

Exercise is like medication. This is where it gets complicated for people on insulin or on other medications that can produce hypoglycemia. While it is true that regular exercise helps you better control glucose levels, lows before the insulin doses are adjusted can assert themselves after just a few days of regular exercise. This is where you recommend that “your diabetes health care provider may change or adjust your medications based on the results recorded in your diabetes record book.” From experience, I can say that it is hard to anticipate which night this will happen--and it always seems to be at night when it happens--unless you anticipate needing less insulin before you actually experience a low. Recall also that most physicians are not available to review a record book at the drop of a hat. There has to be something that can tip a patient off before having to risk whether the low will wake them up. Any ideas?

Barbara

March 17, 2015 12:09 p.m.

Is there a certain amount of glucose in the bloodstream that causes problems

Linda bonebrake

March 17, 2015 11:45 a.m.

Balancing exercise with insulin injections is truly a challenge that can cause a great deal of anxiety. The fact is that it is not a normal way to live, but what choice does one have? One must stay active as possible and try to manage the ups and downs of blood sugar fluctuations. Perhaps one day, easier methods of blood sugar monitoring will be made possible and other methods of regulating glucose levels will help people with this condition live an easier life. Better yet, perhaps, one day, diabetes will be eradicated.

George

November 13, 2013 9:50 p.m.

I think the hard part is getting to admit you have it and that as young as you are people of all ages and fitness levels get. Its a mental nightmare at first. Lean on friends and family.You are not alone! With care,diet,meds,exercise,and patience. LIFE WILL BE GOOD!

Rocky

September 29, 2013 8:34 a.m.

You read a lot about exercise and insulin, but I often wonder what adjustments should a DM non-insulin dependent should make prior to exercising? Plus, what are good source of 1 or 2 carbohydrates intake?

Minnie

September 22, 2013 2:57 p.m.

must disagree with your advice about not exercising before bed. in my opinion their should never be any type of discouragement to exercising. benefits from any exercise far outweighs possible side effects. of course you can find extreme situations where their are adverse affects but for the 99.9% who will benefit their should be overwhelming encouragement. i credit exercising (and diet) with going from a a1c of 12 to an a1c of 5.5 without any medication.i'm not any kind of fitness freak at still over 275 lbs. i have been able to swim(very slow pace) and walk. just an average american who let their weight get away but through peoples encouragement to exercise even a little when i could good things have been happening for over a year.

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